Sheet folding machine



July 10, 1956 R. L. SJOSTROM SHEET FOLDING MACHINE 4 Sheets-Sheet 1 Filed Sept. 2, 1950 I N V EN TOR. Robert s o'k'r m W 7/ y 1956 R. SJOSTROM 2,754,113

SHEET FOLDING MACHINE Filed Sept. 2, 1950 4 Sheets-Sheet 3 7 l4 glO FIG. E

INVENTOR.

Robert L. sy'sr'm July 10. 1956 R. L. SJOSTROM SHEET FOLDING MACHINE 4 Sheets-Sheet 4 Filed Sept. 2, 1950 m l F.

INVENTOR. Robert L. 5 ''sr'm J BY MA? United States Patent 2,754,113 SHEET FOLDING MACHINE Robert L. Sjostrom, Andover, Mass. Application September 2, 1950, Serial No. 183,063 Claims. (Cl. 270-84) The present invention relates to a machine for folding sheet materials and also for stacking and counting the same and is an improvement on my copending application, Serial No. 15,065, filed March 16, 1948, now Patent No. 2,545,798 of March 20, 1951. The apparatus employed in my prior application carries a piece of material as for instance a laundered towel, curtain, pillow case or similar article over a conveyor on to a table where side folding plates operate to provide longitudinal folds of the sides after which the material continues its travel longitudinally of the table, whereupon a transverse fold is made and the sheet carried thereafter to a stacker where the pieces are stacked in a heap. The present invention follows the same general arrangement as far as the routine of folding is concerned but is an improvement thereon in the method and apparatus employed in the system.

In the present invention the longitudinal folds are effected through pneumatic means simply operated while the transverse folds are made without contact with the sheets being folded by an air blast alone.

Other and further advantages of the present invention will be more readily understood from the description in the specification set forth below in connection with the drawings illustrating an embodiment thereof, in which:

Figure 1 shows a fragmentary plan view of the forward end of the machine of the present invention.

Figure 2 shows in fragmentary plan view a detail partly shown in Figure 1.

Figure 3 shows a rear sectional elevation of the apparatus.

Figure 4 shows a section substantially on the line 44 of Figure 3 with part of the back wall of the machine shown in fragmentary view.

Figure 5 shows a section taken substantially on the line 5-5 of Figure 1.

Figure 6 shows a section taken substantially on the line 6-6 of Figure 1.

Figure 7 shows a section in reduced dimension taken substantially on the line 77 of Figure 6.

Figure 8 shows a fragmentary detail shown in Figure 6.

Figure 9 shows a circuit diagram for effecting the side folds of the material in connection with the longitudinal feed of the material.

Figure 10 shows a modification of the arrangement shown in Figure 1.

Figure 11 shows a modification of the detail of Figures 3 and 4; and Figure 12 shows a further detail shown in Figure 2.

In the present invention referring more particularly to Figure 1, the material to be folded, as for instance a towel, pillow slip or other fiat fabric is fed on to the conveyor belts 1,1,1, 2,2, 3,3,3. These belts all run parallel to one another with group numbered 1 on one side of the machine; the other group numbered 3 on the other side of the machine and group numbered 2 in the center of the machine. The material to be folded is normally fed with the mid-line of the material substantially coin- 2,754,113 Patented July 10, 1956 ciding with the center line of the machine which is between the two central conveyor belts 2,2. The end of the conveyor table section 4 may be angularly adjusted as it is hinged at 5 to a central table section 6. When the material approaches the central table section 6, the side conveyors 1 and 3 raise the material at the sides because of the upwardly inclined fingers 7,7,7, on each side of the machine, which at their raised ends lie over plates 8 and 9. At the center section of the machine the material is conveyed beneath the plate 10. The plates 8, 9 and 10 which correspond to similar plates shown in my copending application previously mentioned serve to effect the side or longitudinal folds. Beneath the plate 10 there is provided a clamping member 11 which is automatically operated by the photocell element 12 which reacts after the rear end of the material has passed over it to bring the clamp 11 against the inside of the plate 10 and stop the motion of the material over the center set of conveyors 13 during the time that the side fold is effected. The arrangement for this may be operated as described in my copending application but is preferably controlled in coordination with the operation of the movement of the cross plates 8 and 9 inward and outward with reference to the center line of the machine as illustrated by the circuit diagram of Figure 9, the operation of which will be explained more fully below.

The side plates 8 and 9 (see Figure 6) are positioned horizontally at a higher level than the center plate 10 with the plate 8 positioned slightly higher than the plate 9 so that it will pass over the surface of the plate 9 in the intervals that the two side plates are over one another.

As indicated more clearly in Figures 7 and 8, each side plate is supported by an upwardly extending bracket 14 to which a sleeve 15 is attached. The sleeve 15 is fitted to slide on a shaft 16 which is supported by each side 17 of the frame. The sleeve 15 is also supported by a horizontal extending bar 18 at the end of which are two free rollers 19 slidable in brackets 20. This whole mechanism is operated by pneumatic means which comprises a pneumatic cylinder 21 in which a piston rod 22 reciprocates to move the plate assembly on its slidable mounting. The piston rod 22 has attached at its end a bracket 23 which has a horizontal extending part 24 which is fastened to the bottom of the plate 14. The bracket 23 carries a projecting finger 25 which engages in its cross-wise motion two switches LS4 and LS5.

The system which has been just described is duplicated for both the plates 8 and 9. In the case of the plate 9 the operating pneumatic cylinder is 26, operating finger 27 and the switches LS2 and LS3. The cylinders 21 and 26 are mounted in fixed position under the table by any suitable means as indicated in Figure 6 by means of collars 28 which are attached to the bars or plates 29 and 30 on which the switches are positioned. As indicated more clearly in Figure 7, the switches LS2 and LS3 are operated only by the finger or arm member 27 and the switches LS4 and LS5 only by the finger or bar member 25.

Referring now to the circuit diagram of Figure 9, the switch LS1 is related to the photo-cell 12 so that when the fabric, slip or towel passes over the photo cell, the switches LS1 controlled by the photo-cell are operated. The switch LS1 comprises a single pole double throw relay switch with one section LS1 shown in Figure 9 as open and the other section LS1 shown as closed by the cross lane through the switch which is the notation employed in Figure 9. As the towel or cloth begins to pass over the photo-cell, the switch LS1 indicated as open in Figure 9 is closed and this energizes the coil CR1 which operates the holding switch CR1 to provide a holding circuit. When the cloth has passed beyond the photo-cell the first half of the switch LS1 opens and the second half LS1 closes which is the switch shown as closed in Figure 9. In this position the solenoid controlling :the clamp 11 is operated and the cloth or towel is immediately held temporarily from further motion. With the switch LSlclosed as shown in Figure 9 and the holding coil CR1 energized, the coil CR2 becomes energized which in turn closes the switches CR2 and CR2 and the hold solenoid CR2 and maintains a closed circuit so that the transformer 31 becomes and remains energized. The primary of thetrausformer 31 is therefore connected across the supply line and the secondary of the transformer is connected with the switches LS2, LS3, LS4 and LS5 which control through solenoid coils 33, 34, 35 and 36 the valves .for the pneumaticallyoperated cylinders 21 and 26.

The switch CR3 which is normally closed causes the solenoid coil :33 to becomeenergized as soon as the transformer 31is energized which thereby operates the piston 32 by permitting air to enter the pneumatic cylinder 26 and the piston 32 in Figure 6 is moved to the left for successively operating the switches LS2 and LS3. Operation of LS2 closes relay LS2 and energizes solenoid valve 35 for starting the piston 22 of cylinder .21 on its way inward carrying plate .8 towards the center. At the same time the piston 32 actuates LS3 both parts, which closes CR3 and CR32 at the same time energizing the holding coil CR3 and deeuergizes CR3 thus closing the valve sending the piston 32 forward and energizing-the return valve solenoid 34 for returning the piston in the opposite direction.

As the piston 22 starts inward it actuates successively .the switches LS4 and LS5. -Meanw'hile the switch LS2 has opened as the piston 32 reverses its direction on return so that the solenoid valve 35 is closed and actuation of the switch LS4 closes the switch for energizing the solenoid 36 to begin the return of the piston 32. Since however'the piston 22 has a certain momentum it will continue slightly beyond the switch LS4 and operate the switch LS5 which opens the switch LS5 from the closed position .shown in Figure 9 and then as it travels back moves toclose the switch LS5. By opening the switch LS5, the whole system becomes energized and by closing the switch LS5 quickly thereafter the system is restored to a position where the operating cycle may begin again.

It is .evident from the description above that first one sideplate starts inward to the center by operation of the switches controlling the solenoid valves for the cylinder and then the plate on the other side begins to travel inward while the first is still travelling inward. The first plate which begins to travel, however, has a phase advance over the second plate and completes its cycle. In fact the first plate travels outward while the second plate travels inward. By first plate and second plate in the above-mentioned description, the sequence of operation onlyis referred to.

After the towel has been folded on each side and the holding coil LS1 is released by opening of the switch LS5, the folded towel continues its travel over the conveyor belts 13 passing over the cross folding rolls 37 and 38 over which is positioned an air blast pipe 39 (see Figure 5). The material is then carried over the plate 40 from which it is picked up by the conveyor belts 41 until it intercepts the light cell beam directed at the photo-cell 42. This photo-cell may be positioned at the desired distance from the rolls -37-and. 38 so thata cross center fold may be made in the piece to be folded, The position in the cell 42 and the light source above it is adjusted on the slide frame 43 and 44 by means of a bracket 45 which may be positioned and clamped along the frame 44 by means of a'clamping nut 46. The rolls 47, 47 and 48, 48 carry thebelt 41 and the towel or other material will travel outward along the conveyor belt .41 until it is centrally positioned between the 'rolls 37 and 38. In'th-is position the airblast pipe 39 will be operated to send a blast of air against the material and force the material between the rolls 37 and 38 which will provide a cross fold and send the folded sheet or towel on to the conveyor belt 49 (see Figure 3) from which it will be fed to the stacker 50.

With reference to Figure 3, the sprocket gears 51 and 52 are the gears for operating the rolls 37 and 38 and the gear 53 is the gear for operating the rolls 47, 47 for driving the conveyor belt 41. This drive may be effected by a chain drive as indicated by the chain 54. As shown also in Figure 3, the power supply for the system is opened through a motor 55 which drives the sprocket gear 56 and chain 57. A gear, not shown on the shaft 58 drives both the sprocket gear 54 and the chain 59 which drives the shaft and roll upon which the conveyor belt 49 is mounted. The folded sheet from the conveyor 49 is conveyed over a second conveyor 60 to the stacker 50 which differs from the usual stacker by the arrangement indicated in Figures 3 and 4.

In this arrangement the conveyor belt .61 which is driven by t e roll 62 at the forward end of the stacker goes around theroll 63 forming an endless belt arrangement. In accordance with the standard stacker, the towel or article as it passes along the conveyor .61 hits an arm 65 of a switch, not shown, which operates to raise a table 66 and lift the folded piece on to the rack formed by a series of bars 67. This arrangement is quite standard in the industry of folding and since it in itself does not form a part of the present invention, will not be described in detail.

The ends of the towels or pieces which are folded will all .be lined up in uniform fashion since each end will Come against .a fixed plate ,67 (Figure '3). The operation of the switch arm 65 which in each case raises-the folded elements to the stack also operated a counting member shown diagrammatically by a block element 68. The counter in turn causes the operation at selected positions as for instance every 50th operation of the solenoid 69 which pulls .down the plunger 70 for operating the bar or lever 71 (see Figure 4) pivoted at 72 for raising the shaft 73 .on which the conveyor belt roll 63 is mounted. This operation of raising the shaft 73 will tilt upward the conveyor belt 61 so that the article travelling along it will pass over the top of the back stop 67 and come against the back stop 74 so that theparticular piece which is operated on the selective setting of the counter 68 will project beyond the rest of the pieces in the stack and show the count from the previous stock.

A modification of the arrangement shown in Figures 2 and 3 'is illustrated in Figure 11 in which the endless belt travels around a roll 81 which is mounted on a shaft 82 which remains in a fixed position but free to rotate. Beneath the support 61 at its end next to the first back stop 83 is an air vented pipe 84 which extends cross-wise of the stacker. This pipe is fed through the feed pipe 85 and the air blast is controlled by the solenoid valve 86 which operates in conjunction with a counter 87 so that when the sheet of the particularly desired count operates the switch arm 65, an air blast is sent through the vents 87 up against the bottom of the folded sheet of material which is thereby blown upwards over the first stop 83 and carried by the conveyor belt 80 to the second stop 88. The rest of the mechanism is-similar to that described in connection with the Figures 3 and 4.

A modification of the arrangement of Figure l is shown in Figure 1-0. Here the plates 98 and 99 corresponding to the plates 8 and 9 are fixed and not laterally movable. Between the plates 98 and 99 is the fixed plate 100 and positioned slightly beneath these plates are air vented pipes 101 and 102 each with a series of air vents 103 and 104 respectively. An electronically operated clamping plate 1-05 is positioned beneath the plate 100 and this is operated similarly to the one described in connection with Figure 1 for stopping the sheet material at the proper 75 point. The sheet to be folded is carried over the plates 98 and 99 and beneath the plate 100 similarly as described in connection with Figure 1. When the sheet has passed by the light cell, the clamping plate 105 operates to hold the sheet and thereupon suitable solenoid valves release air through the vents 103 and 104 of the pipes 101 and 102 to efifect a longitudinal fold of the material on the machine. The valves operating these blasts are timed similarly as described with the operation of the plates but need only to be operated by a single solenoid to cause a single air blast from each pipe in successive intervals timed so that each fold will be effected successively and not together.

Figure 12 shows a detail of the light cell system. In this case the photocell 42 which controls the cross fold and the operation of the air valve admitting air through the vents of the pipes 39 receives a beam of light from the light source 106 which may be carried by a bracket 107 supported from the bracket 45 which carries the photocell assembly so that as the photocell is moved in its proper position, the light source will also occupy a position directly above it. This is adjusted lengthwise of the machine so that the sheet will be folded cross-wise at its center as it is forced between the rolls 37 and 38. if it is desired not to make a mid-fold or if different size sheets are to be folded, the whole assembly may be adjusted to the desired position to effect this result.

The invention has been described simultaneously with an explanation of the method of operating the apparatus elements forming a part thereof and therefor no further discussion will be devoted to the operation of the machine.

Having now described my invention, I claim:

1. in a system for effecting parallel folds of sheet material, means comprising a central plate and side plates, means for feeding the sheet material under the central plate and over the side plates, a holding element having a clamping plate positioned beneath the central plate, electronic means having elements operative on the approach of the sheet being fed and on withdrawal of the sheet being fed to bring the clamping plate against the central plate, pneumatic cylinder and piston means for each of said side plates for moving the same inwardly of the central plate and outwardly thereof, and means included in said electronic means operative by said elements for initiating the operation of said pneumatic cylinder and piston means and switching means also included in said electronic means for establishing a cycle of operation of said pneumatic cylinder and piston means in which the first piston traveling inwards causes the second piston to follow in similar opposed motion after a predetermined time interval.

2. In a system for effecting parallel folds of sheet material, means comprising a central plate and side plates, means for feeding the sheet material under the central plate and over the side plates, a holding element having a clamping plate positioned beneath the central plate, means including switch means positioned in the path of the sheet to be folded for operating the clamping plate when the end of the sheet to be folded comes between the central plate and the clamping plate, electrical means operative by said switch means and means operatively controlled by said electrical means for moving the side plates over the central plate and further electrical means connected for operation of said side plates in a complete operating cycle including switch means positioned in the machine so that the movement of the side plates will operate said switch means for controlling the sequence and timing of the motion of the side plates in said complete operating cycle.

3. In a sheet folding machine, means for effecting parallel folds of sheet material comprising a central and side plates positioned substantially parallel to one another but at slightly different levels, means for alternately moving first one side plate and then the other laterally from the side to a position over the central plate and then returning them to their normal side position comprising two pneumatic cylinders mounted transversely of the folding machine at opposite sides thereof, each of said cylinders having pistons, means connecting the pistons one to each of said plates and electrical switching means including means initially operative by the position of the sheet on the machine for controlling the movement and sequence of operation of said pistons and the plates moved thereby.

4. In a sheet folding machine, means for feeding material to be folded longitudinally of the machine, means comprising a central plate under which and side plates over which said material is fed, means for holding said material to be fed against the under side of said central plate, means for alternately moving first one side plate and then the other laterally from the side to a position over the central plate and then returning them to their normal side position comprising two pneumatic cylinders mounted transversely of the folding machine at opposite sides thereof, each of said cylinders having pistons, means connecting the pistons one to each of said plates and electrical switching means including means initially operative by the position of the sheet in the machine for controlling the movement and sequence of operation of said pistons and the plates moved thereby and electrical means controlled by the position of the material for op erating said holding means.

5. In a system for effecting parallel folds of sheet material, means comprising a central plate and side plates, means for feeding the sheet material under the central plate and over the side plates, a holding element having a clamping plate positioned beneath the central plate, means including switch means positioned in the path of the sheet to be folded for operating the clamping plate when the end of the sheet to be folded comes between the central plate and the clamping plate, electrical means operative by said switch means and means operatively controlled by said electrical means for moving the side plates over the central plate, and further electrical means for controlling the sequence and timing of the motion of the side plates in a complete operating cycle to which said plates they are operatively connected including a plurality of switches positioned to be operated by the moving side plate with said last mentioned switches operatively connected to said means for moving the side plates.

References Cited in the file of this patent UNITED STATES PATENTS 229,419 Jones June 29, 188 0 264,364 Stocking Sept. 12, 1882 455,065 Stebbins et a1 June 30, 1891 684,286 Millhiser et al. Oct. 8, 1901 936,711 Goss Oct. 12, 1909 1,719,833 Deligianes et al July 9, 1929 1,807,170 Peterson May 26, 1931 1,811,618 Dudley June 23, 1931 2,063,156 Gabbert Dec. 8, 1936 2,101,328 Broadmeyer Dec. 7, 1937 2,268,036 Kahn Dec. 20, 1941 2,443,779 Sanders et al June 22, 1948 2,545,798 Sjostrom Mar. 20, 1951 2,583,746 Peterson Jan. 29, 1952 2,624,990 Allen Jan. 13, 1953 

